P0251 DTC in 2003 Ford Mondeo TDCI: No Start After Injector R&R and Recoding
My 2003 Ford Mondeo 2.0L TDCI (Delphi injection system) has developed a no-start issue after I performed an injector removal and recoding using Snap-On Verdict. The vehicle has reached 154,000 miles. After removing the injectors for reprogramming, I refitted them, bled the system, and attempted to start the engine. However, it now fails to start with a DTC P0251 indicating a fault in injector signal detection. Fuel is visibly gushing from the injector pipe unions during cranking, and live data shows an extremely high rail pressure of 320 BAR — suggesting fuel delivery is occurring but not being properly injected into the cylinders. The engine runs briefly on brake cleaner, indicating that there is no proper fuel injection in the combustion chambers. I have already checked and replaced both cam and crankshaft position sensors, as well as the fuel filter, with no resolution. I am now concerned that the injector removal and reinstallation may have caused internal damage or clogging due to contamination. The vehicle has an automatic transmission, so towing is not a viable option at this stage. I cannot believe that simply removing and reinstalling the injectors could cause such a failure — especially given that fuel flow appears normal. Any insights into potential causes of P0251 after injector service would be greatly appreciated.
Hi, you don't need to remove the injectors to access codes — they are often visible on the back of the injectors using a mirror. There may also be a sticker on the rocker cover showing the stored fault codes. It's possible that your injectors have accumulated dirt or oil contamination, even in small amounts, which can damage or block the nozzles. This could explain why the engine fails to start after reinstallation. Cleaning or replacing the injectors might resolve the issue. Cheers.